Ceramic or plastic Discs (or a durable metal, say titanium), where a grid of ones and zeros in encoded by holes, much like punch cards of old to store data. Using a durable enough plastic metal, or ceramic, you could laser etch the holes (as well as read the data back using the same method. On a more
commercial note, you could provide heavy plastic "CDs" and use them for "archive quality" storage, providing a more permanent solution to the problem of CD, and magnetic media aging and environmental impact.

Years ago there was a project called homeCD that printed with postscript to create an ISO image using a printer, transparency paper, and foil. Printed ISO's were VERY lowe capacity, but work great. You could also make ISO images by burning the holes in this way so that a standard CD rom could read the archive disk.

The problem with archving something forever is that languages themselves get lost. I am sure the Egyptians thought they were archiving their stuff forever but even what did make it to us did no one any good until we learned what the picture of a man with a bird for a head was supposed to mean. While these discs will be durable and stand a better chance against time they ultimately face the same problem. Who is to say that 2 thousand years from now there will be a binary language?

Though as simply a medium for "long term" archival (hundreds of years instead of thousands) it seems like a fine idea.

Reminds me of the cuneiform tablets that have come down to us with Linear A and B on them.

Apparently they were originally made by making impressions in wet clay, which would then dry. Once the tablet was done with, the tablet would be mixed with water again for reuse. The only reason the ones we have survived the ages was that the palace or library they were in was burned to the ground in a raid or invasion, thus firing the clay and making it last.

But it does suggest that we could do something similar here. Well, not burning the house down or having someone invade us, but converting those temporary files we want to keep for the millennia to some high impact polymer or ceramic. (Perhaps distantly future generations will see archeologists who have deciphered this ancient MS Windows language, but are stumped by Apple Macintosh.)

And I'm picturing our long distant descendants, bespectacled in drafty university libraries, struggling to piece together blogs and chat sessions.

//Why couldn't you use tiny little connect-the-dot pictures to establish a language that is then used to describe the process by which the rest of the code is to be deciphered?\\

Drawing little images is possible but perhaps not the best solution. As a more complex (non-binary) encoding it may degrade more quickly than the data it describes.What you need is a sort of tutorial explaining the format for interested parties. I had an idea on how to do this (linked).